Beautiful set of Sudoku's, thoroughly enjoyed solving the test! :)

Done - The biggest gainer is luboign who moved from 79 to 56.

Players are requested again not to do this. It is waste of time and error-prone.

Great set of puzzles. For me a bit disappointing, as I got caught in a misinterpretation of the Quad Sum rules. The phrase that "numbers may repeat around the arrow", I interpreted as "there is no number larger than the number the arrow is pointing at", which meant that for instance I could not exclude the 5 in R8C6. That made the puzzle significantly more difficult, and in the end unsolvable. Cost me a lot of points :(

Congratulations Serkan for a superb test, Rishi for finishing at #1 and Rohan for finishing in Top 11 !!!

In his series of "Puzzle analysis of the week", Nikola has chosen Double Diagonal and Pandigital for this week.

Read more in his blog - http://logika-nikola.blogspot.com/2011/07/analiza-nedelje-3.html

I got completely stuck on the Odd-Even-Big-Small sudoku during the test - put it away after having wasted about 7-8 minutes, and tried it again this morning. Well, it was hard but I nearly reached the end. But there, I found several solutions. No mistake as it seemed, so I searched again and again, wondering what I could possibly have missed. Nothing.

Then I finally read the rules and noticed that they clearly said : "An indicator symbol on the outside says that the first two numbers along that row or column are either odd (1,3,5,7), even [...]


*kick myself*


Anyway thanks again Serkan, I had fun even on sudoku types I tend to dislike.

Hi,

First of all thanks to all participants for spending two hours :)

Congratulations to Rishi Puri, Jan Mrozowski and Hideaki Jo. All three of them took their strategies wisely and all three gained more than 700 points in the first 70 minutes. Hideaki Jo started the test with an amazing performance as he mentioned, but couldn't keep it up. Jan Mrozowski also started well, but near the end he had 3 or 4 broken puzzles. What I admired about him was that he realised and corrected 2 or 3 broken puzzles in the last few minutes. This really shows his confidence. And the winner Rishi Puri, first of all I am so happy to see a new champion. He too started very well and progressed consistently until the end. With the points 779-227-125-40 according to the four stages, he was the only one in the top three to achieve "most points in first stage, least points in last stage" theme.

I am happy that the scoring system worked out well. In my opinion, this kind of scoring shouldn't contain time bonus. Because the author is supposed to design the puzzles in a way that forces the competitor to take a strategy, and time bonus in a twist scoring like this is not so reasonable. The author must be sure of the difficulty of the set and must be sure that there is no need for time bonus. Honestly I was not so sure about the difficulty and I gave time bonus, because in the case that a few solvers completed the test, there could be an unfair scoring due to the twist structure. For example I was so sure about the TVC series, but there happened to be an unfair scoring due to lack of time bonus, so I didn't want to take a risk.

The puzzle with the highest rating was Number 5 Still Alive - 9.5
The puzzle with the lowest rating was Just One Cell - 5.71
221 people started the test and 199 of them submitted at least one answer.

Thanks again to all participants, WSC organizers, LMI, Deb Mohanty, Gulce Ozkutuk Yurekli and Salih Alan.

Best

Serkan

I also enjoyed the test a lot. Great puzzles!

I don't really think the point system has more advantages than disadvantages, but honestly I don't really care either way. One disadvantage is that there are several deadlines to watchduring the test:
I began with those puzzles I thought I was best at. Of course the high-pointers first. Then before the 70-minute deadline I solved several low-pointers. After the 70-minute deadline I began with high-pointers again. I should have done the same (switching high-pointers with low-pointers) at the 90-minute, 105-minute and 120-minute deadline, but for me that would have taken too much concentration away from the puzzles. Thus I ignored all deadlines except the 70-minute and 120-minute deadline...

Stefan

[edit:] There were a lot of forum comments from competitors while the event was still running. Comments on puzzles - how innocently they might be intended - should not be posted. Before taking the test I browse the forum thread of course. I am not happy to read which solvers had problems with which puzzles or which puzzles they were happy to have tackled. It is not easy to let oneself not be influenced in ones own choice of puzzles.

Edited by euklid 2011-07-18 6:47 PM

I completely agree with this. I understand it may be difficult to restrain oneself from talking about the puzzles we just solved, but it really is necessary to avoid influencing other players. To deal with this, I usually post a first message right after having completed the test, in which I usually complain about my poor performance due to many mistakes, blah blah blah, and then a second one once the test is over, in which I talk about puzzles themselves.

Please keep it in mind for the future, it will be highly appreciated... at least by Stefan and I.

It looks like a few of us (Kota, David McNeill, certainly myself) took the general approach to just solve this test, not to strategize which puzzles to solve, and enjoy the WSC experiences in order. This was much more fun for me (and I think I prefer playing the sudoku contests for fun and not high stress, which it would have been if I remembered where the 3 intermediate time cutoffs were so I'd jump to small puzzles to finish those with one minute before the change or something).

I find assigning accurate points on puzzles for all competitors to be very difficult, so my favorite round design in all circumstances is a test that can be finished in 80-90% of the time so the order of finish determines the top solvers, not which order they solved things in or which puzzles they chose to solve if the round is not finishable. This test was almost perfectly timed, but the top solvers just made some typos or had errors so no one was clean. With this being the case, I'm not sure I see the need for complicated scoring which can make the competition more stressful and take away from the beauty of the puzzles which were, as I said earlier with no specific names as euklid/oursbrun would want, outstanding.

On their point, one thing the UK site did during a past test was add a comment box to their answer sheet. So all the comments about "I think I made an error on X because of Y" can be sent as private messages and not put in the forum. This won't eliminate all the messages here that could contain spoilers, but it is worth considering.

Edited by motris 2011-07-18 8:41 PM

Awesome performance from top players ! congrats !

As said euklid, the disadvantage of this system is to have a lot of "deadlines". When I solve on paper, I don't like to do goings and comings between the place I solve and the computer to submit codes. One must be careful about time much more than on other tests, and can't be as concentrated as you should on grids.

Another little criticism about this system:
I find that it's a great quality to be able to stay concentrated after having solved grids for 1h30 or 1h45. Players that can keep a fast rythm or even increase rythm of solving in the end of test are not favored by this system.

About the test itself: grids were really good. I particularly appreciate distance, quadruple (the grid I solved during test without having the idea to submit it !), number 5 still alive, Quad max, Group sum, thermometer and double diagonal.

I had trouble with 2 power cut during the test, so I wasn't very concentrated about grids and deadlines... I had to finish to print grids after 50 minutes (1rst time it just printed the 12 first grids). I concentrated to try to submit between the power cuts and hoped it'll not last more than 2 hours.



I easily saw that... when I solved the grid after the test completely missed that during the test, I spent about 10 minutes on that grid without being able to go further to this point. When I redo this after the test, I was angry not having seen that during the test !

Fred

Sometimes, it's useful to solve grids of the IB . I say that because it happened exactly the same thing to me on solving the IB grid

Players who made mistakes during Nikoli Selection would have noticed a "Claim Points" button next to each of their wrong puzzle in the score page. Authors / organizers periodically checked all claims as well as all other wrong submissions. I was not exactly keen on adding a text box, primarily because I didn't think a player should explain what mistake he did. It should be left to authors/organizers to deduce if the submitted answer deserves 100% or 80% or 0% independent of the participant's version.
I didn't follow the same model in this test because I just copied Twist's score page this time. So next test onwards, players will see "Claim points" button in the score page. If a textbox is really needed there, that can be done as well.

However, in this test, and in most of the tests, it is not "claiming points" which reveals more about this test. To be precise, apart from Neeraj's claim in this test, there were no other claims. It is mainly comments like "I took x seconds for puzzle y" or I couldn't solve puzzle x in y hours" should be avoided.

As Thomas has observed, I simply tried to solve the Sudokus in order. This was much less stressful than continually shuffling bits of paper. In my case, it took 10 minutes for the first puzzle to be printed (as the pdf file was very slow to open and printing was also incredibly slow). As a result, the unusual scoring system really penalised me. My strategy was also flawed by the fact that I got really stuck on the Distance Sudoku. I would prefer a conventional scoring system.

Some beautiful puzzles, including those which I solved afterwards. Particularly liked Number 5 Still Alive, Group Sum and Odd-Even-Big-Small.

Really surprised to hear that, because the pdf file size was really small (~100 KB), and all grids were vector based images (except some part of odd-even-big-small).

Did anybody else face the problem?

I would second david's point on the fact that puzzles should be sequenced as per points,
but i loved the time based scoring system, knowing your strengths and selecting the right strategy should be rewarded

can any body help out for how to start the "crossnumber sudoku and number 5 still alive"?

Edit : Removed a link not related to sudoku / puzzles

Edited by debmohanty 2011-12-08 9:15 AM

Crossnumber: There are just 4 3-long and 4-long numbers. Not too hard to find their places. Four instance in the 1st row the 3-long number can be just one from the list.
After the 3-long number in the last row also unique. You can put the other two 3-long number easily.
Now you can find the places of 4-long numbers.


Number 5: A bit harder (it is 78 points)

Four instance in the left-middle box there are 3 cages. The sum 5+5+15 or 5+15+15 But the second isnt good, because the total of remained cells would be 10, and a 6 is given. So it is 1+3+6, but R3C1=3
Hence the correct sum 5+5+15 so this 3 cages contain (2+3) (1+4) (7+8) and the 2 remained cells (5,9)
You can consider the other side as well, the 2 remained cells (1,5)

You could write down numbers, but these are important informations.

If you look at the 5th column you will see 4 cages. The total of this cages 40 or 35 or 30 etc. So 40. And R5C5=5. The number pairs in this column (14) (23) (69) (78) and just one cell can be 9. (R3C5) Now you can find the 9 and 6 in the right-middle box. (5,9) in the left-middle box and (1,5) in the right-middle box. Moreover all 9s unique.

I hope this will be enough.